Paper-making machine



Feb. 28, 1928.

E. V. ASTEN PAPER MAKING'` MACHINE Filed Maron i2, 1927 d we 3H@ fob -7520el2zn' daad u Patented Feb. l28, 1928..

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Now, the invention has for .its object to,

UNITED STATES PATENT OFFICE.

vEIDU'AIR'II) V'. ASTEN, 0F EUPENQ BELGIUM.

paran-MAKING MACHINE.

Application 1ed`March 12, 1927, Serial No.

Iii paper makin machines the drying of the paper web is e ected by evaporating the moisture on the so-called drier part in which w -the paper web is conveyed by the aid f drier felts over heated drying cylinders. A good drying can only be obtained ithere eX- ists a sufficiently large surface area at which the evaporation can take place. This surface is formed by the paper web itself and by the drier felts which come into contact with the paper web and abso'rb moisture from the same. The moisture absorbed has to be evaporated again at the surface' of the felts, which means that the felts have to be dried in their turn. Owing to the construction of the papler making machines the vapors rising from t e paper and felts can only draw oli badly and large quantities ofthem remain hovering in the machine whereby, of course, the process of evaporation 4is seriously iinprovide the drierpartof paper making machines with means by which'hot air for drying` the paper web and felts is introduced into. the machine in such a manner thatit comes into contact with the surfaces of the paper'and elts and at the same time carries the vapors out of the machine.

It wouldnot be preferable to simply blow hot air into the free spaces ofJ the machine fromoneof its sides, because in that case the aper web would dry more uickly at the 'Blowing-in side, i. e.,it woul not dry uniformly. Besides, the hot air would choose the most open` ways and would not come to thepoints where ventilation is worst.

According to the invention, rotating Atubes are mounted in the machine transversely thereof, these tubes being supplied with hot air and having iii their walls slots through which the hot air ows out in a current which constantly changes its direction owing tothe rotation of the tubes. The said slots are' referably arranged in the tube walls 'on 'elical lines so that the air leaving'the tubes -will act like a feed screw and convey the vapors laterally out of the machine.

paper making machines where the arrangement of special hot airtubes' -is not feasible because of a compact construction of the machine,the felt'guide rollers are constructed as hot air tubes according tothe invention. L

The subject-mattei` of the invention is 1745,971, and in Germany November 11, 1926.

illustrated by way of example in the accom'- panyi'ng drawing in which:

Fig. lLis a diagrammatic side elevation of the dryer part of a paper making' inachine comprising special Ihot air tubes and felt guide rollers constructed as hot air tubes, ,f i

2 is a plan view of a hot air tube,

Fig. 3 is a similar view of a slightly modified tube, and A Fig. 4 is a longitudinal section through the tube shown in Fio. 2.

In Fig. 1, a, are the drying cylinders, b

lis the paperv web; c are the drier felts, d are rotary felt guide rollers which are constructed as hot air tubes, and f are special hot vair tubes which are rotatably arranged -inj the transverse direction of the machine. The arrows show how the air currents leaving the hot air tubes iiow against the surfaces of the -paper web and drier felts.

slots e are arrangedon a line extending helically around'the tube. In operation, the hot air leavin the tube through the slots acts like a fee screw and carries the vapors away towards one side of the machine. This type of tube is to be used if it isintended to carry the vapors laterally away for pro- .tecting the attendants, who are assumedto be standing at the opposite side of the machine, against the heat and the vapors. The `said type of tube may also be used with advantage if it is intended'to arrange at the. particular side of the machine towards which the vapors are carried, a special drawing-oil device for the vapors.

In the form of tube according to Fig. 3 the slots e are arranged on' two helical lines which extend from a common point in the transverse middle plane of the tube in opposite'directions to ,the ends of the tube.

The supply of the hot air to the tubes tl, f takes r'place at one end, as indicated at w in Fig. 2-4, while the other end of Ithetubes is closed. When blowing air into a tube of the'kind described, the pressure and velocity los uniform. In order to overcome this drawback the tube is provided in its interior with a cone-shaped body g. The air will ow along the outer surface of the cone g. The cone causes a gradual reduction of the air space or sectional area of the tube towards the closed end of the tube. crease of the sectional area of the tube is made to correspond with the increase of the area of the air slots e in the direction towards the closed end. It is thereby rendered possible to maintain the hot air at a substantially uniform pressure throughout the entire length of the tube and to produce a uniformly strong air motion throughout the width of the machine.

. In many cases it will suffice to construct only the felt guide rollers as hot air tubes. New elements or machinery parts are then avoided and the rollers besides guiding thel felts operate as hot air tubes. The rollers are heated and allow the hot air to enter into the spaces .which are otherwise dilicult to reach.

The fact that in operation some slots of the felt guide rolle-rs are covered by the felts is of no importance, since a sufficiently large number of slots through which the air may flow out remains always uncovered.

Forming the felt guide rollers into hot air tubes of the kind described makes it possible to apply the invention without any difficulty to machines already existing.

The described tubes or rollers may also be used for drying other fibrous webs.

'lhe means for properly mounting and rotating the tubes and supplying `hot air to them may be of any suitable kind. For eX- ample, the tubes f may be driven from pulleys h on the shafts of the cylinders a through the medium of belts 'i cooperating with said pulleys h and with pulleys k on the tubes f.

Having thus described my invention, I claim as new and desire to secure by Letters-Patent, is

l. In the l machine comprising drying cylinders and felts for conveying the paper web over these c linders, rotary tubes mounted in the mac ine transversely thereof, one endof the tubes being open for the introduction of hot air into the tubes, air outlet slots arranged on helical lines in the c linder walls of the tubes, and means in the tubes for gradually reducing the section of passage from the air nlb end towards the opposite end lof the 2. In a drier part of a paper-making This gradual de# vthereof o en to the whatv p drier part of a paper-making tween the paths of the paper web and felts, said tubes being formed with openings and adapted for the reception of hot air, and means for rotating the tubes to cause the hot air to flow out of said openings in a constantly changing' direction, whereby such hot air currents impinge on the surfaces of the paper web yand felts for drying the same and also remove the vapors accumulating in the machine.

3. A drier means cooperating with the drier part of paper-making machines, comprising hollow cylindrical bodies having a closed end and an open end, and arranged in the free spaces between the pairs of the paper web and felts in said drier part of the paper-making machine, the walls of the bodies being formed with openings spirally Idisposedairially of the bodies, the open ends of the bodies being adapted to be connected to a supply of hot air, and means for rotating the bodies to cause the hot air to pass through the openings in a stream following a convolute path and acting at all times in the same direction to dispel the vapors accumulating in the machine.

4. A drying means for the drier part of paper-making machines, comprising a tube end to a source of hot air supply, the wall of the tube being formed with openings, and means arrange-d interiorly of the tube to gradually reduce the cross-sectional area thereof open to the hot air current from the inletend to the closed end of the tube.

5. A `drying means for the drier part of paper-making machines, comprising a tube closed at one end and open at the opposite end to a source of hot air supply, the wall of the tube being formed with openings and means arranged interiorly of the tube to gradually reduce the cross-sectional area hot ai-r current from the inlet en d to the closed end of the tube, the cross-sectional area reduction of the tube being in such proportion to the area of the openings as to maintaina substantially constant pressure of the hot air throughout the` length Vof the tube.

6. In the drier part of a a/per-making machine having drying cylin ey/s', felts for conveying the paper web overt/the dryin cylinders, uide rollers for the fflts forme of. hollow at the opposite' end toasource of hotair supply, said bodies bein formed with open-l ings to 'dischar e the lliot air: against lthe surface of the fe ts.

In testimony 'whereof I have signedmy"l machine havin drying cylinders and felts fname to this specification.

for conveying t e pa er web over these cylinders, tubes I.arrange in the free spaces be- EDUARD v. As'rnn.

closed at one end and open at' the opposite.

odies closed at one end and open- 

